In the large, slow-speed, loop-scavenged...

In the large, slow-speed, loop-scavenged...

Question 1 of 270705eccefa1bacbc34ba4d4741a

In the large, slow-speed, loop-scavenged main propulsion diesel engine shown in the illustration, the upward motion of the piston draws in scavenging air into the piston undersides through __________. See illustration MO-0003.

Question 1 of 27070

Q

In the large, slow-speed, loop-scavenged main propulsion diesel engine shown in the illustration, the upward motion of the piston draws in scavenging air into the piston undersides through __________. See illustration MO-0003.

No Illustration

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🔍 Key Concepts

• Loop-scavenged two-stroke diesel engines often use the underside of the piston as a pumping space to pre-compress air. • Air drawn into the piston underside must come through some kind of one-way (non-return) inlet device rather than the cylinder ports. • Study the illustration to see which label is connected directly to the space below the piston rather than to the cylinder liner or exhaust side.

💭 Think About

• On the upward stroke, what happens to the volume under the piston, and how does that affect pressure and airflow direction? • Looking at the diagram, which labeled item clearly forms a check/inlet path into the lower space rather than into the combustion space above the piston? • Which option’s description does not make sense as a path into the piston underside—especially considering where the cylinder ports and any turbo/blower are located?

✅ Before You Answer

• Verify which label in the diagram is positioned so that it opens into the crankcase or pumping space under the piston. • Confirm that the device you pick would logically be a non-return (one-way) valve, allowing air in on the upstroke and preventing backflow on the downstroke. • Make sure you are not choosing the scavenging ports in the cylinder wall, since those supply air above the piston, not to its underside.